> That is a> fairly neat idea, and by allowing all combinations of characters from a> subset of the non-alphanumeric characters in operator names, you also> avoid C's problem of parsing +++: It is parsed as a single operator, and> if it is not defined in the program, that is reported as an error.

A better approach is restricted association rules requiring explicit
brackets when some operands are shared by some operators. Typically it is
the cases like:

A and B or C
-x^y

etc. This method will work here as well. Provided, there are

1. infix +
2. prefix ++
3. postfix ++

The rule would be that 1 cannot be associated with either 2 or 3. This
would make both interpretations illegal: